package 二叉树;

public class LC_226翻转二叉树 {

    public static class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;
        TreeNode() {}
        TreeNode(int val) { this.val = val; }
        TreeNode(int val, TreeNode left, TreeNode right) {
        this.val = val;
        this.left = left;
        this.right = right;
        }
    }

    public static TreeNode invertTree(TreeNode root) {
        //遍历：左中右和左右中都可，但不可中序遍历
        if(root==null) return root;
        TreeNode node=root.left;
        root.left=root.right;
        root.right=node;
        invertTree(root.left);
        invertTree(root.right);
        return root;
    }
}
